Storage device and method for providing a partially-encrypted content file to a host device

摘要

A storage device and method for providing a partially-encrypted content file to a host device are provided. In one embodiment, the storage device retrieves a content file from memory in the storage device and partially-encrypts the content file by encrypting some portions of the content file. The storage device sends the partially-encrypted content file to a host device and informs the host device of which portions of the partially-encrypted content file are encrypted. In one embodiment, the remaining portions of the content file are in clear text form and do not need to be decrypted. Because the host device only needs to decrypt the portions of the content file that are encrypted—and not the entire content file—the host device can decrypt the partially-encrypted content file, even if it does not have the processing power to decrypt a fully-encrypted version. In another embodiment, at least some of the remaining portions of the content file are encrypted with at least one additional key.

主权项

1. A method for providing a partially-encrypted content file to a host device, the method comprising:
performing the following in a storage device having a memory storing a content file and further storing an information file specifying a plurality of encryption patterns and encryption keys:
authenticating the host device in communication with the storage device, wherein the authenticating establishes a session key;choosing an encryption pattern and an encryption key from the information file based on the session key;retrieving the content file from the memory;partially-encrypting the content file by encrypting a number of portions of the content file using the chosen encryption pattern and encryption key, wherein the number of portions of the content file that are encrypted is less than a maximum number of portions of the content file that the host device is operative to decrypt;sending the partially-encrypted content file to the host device; andupdating the host device with information that indicates which portions of the partially-encrypted content file are encrypted by sending the information file to the host device.